Corneal endothelial disease is associated with a variety of traumatic, inflammatory, dystrophic, degenerative or toxic insults and commonly results in the formations of a posterior collagenous layer (retrocorneal fibrous membrane). It is strongly suspected that the pathological alterations observed in the posterior collagenous layer (PCL) represent either the synthesis of new species of macromolecules not found in normal Descemet's membrane (DM) or they may be the result of altered assembly of collagenous and/or non-collagenous components normally in DM. In the present investigation the normal human DM and diseased PCL will be isolated and the collagenous and non-collagenous (glycosaminoglycans and glycoproteins) components will be characterized biochemically (two dimensional peptide maps, amino acid analyses, gel electrophoresis, etc.). In addition, tissue culture systems of normal and diseased human endothelial cells (e.g., Fuchs' dystrophy) will be established and the newly synthesized extracellular matrices will be compared biochemically. Presently there is very little understanding of the mechanisms which signal normal endothelial cells to undergo the pathogenic alteration seen during PCL formation. Therefore while human tissues are being studied, we propose concomitant investigations utilizing a rabbit PCL model to study biochemically the extracellular matrices (collagen, glycosaminoglycans, glycoproteins) synthesized by normal rabbit endothelial cells and PCL cells in vitro. We will then investigate possible factors which might regulate extracellular matrix production (e.g., excess or deficient concentrations of fibronectin and fibrinogen/fibrin). Our overall goal in this grant is the biochemical characterization of the PCL/DM complex found in various corneal disorders and for elucidation of possible mechanisms involved in the PCL formation. Hopefully, these data will provide some of the necessary understanding required prior to approaching the problems with a therapeutic intervention.